We are facing MTA related issue on our servers i.e MTA is not processing mails or picking up mails which results in increase in SMTP queue size both inbound and outbound. Once we restart the MEMTAS service it starts working fine. This is happening after every 2 days.
Further we observed in 9.76 mailenable release (http://www.mailenable.com/Professional-ReleaseNotes9.txt) its mentioned about the fix applied for MTA memory crunch issue. Hence we upgraded those servers to 9.79 version as well but the issue still exists.
As a workaround we tried the below :
1. Increased the MTA Count from 8 to 20
2. Executing a cron every 2 hours to restart the service
Kindly help us to fix this issue / bug permanently, as most of our servers are getting affected with this.